Aerobiologia InternatloMI Journal of AeTobiology

ELSEVIER Aerobiologia 12 (1996) 177-184

The aerobiological significance of in Tulsa, Oklahoma

Victoria Crotzer, Estelle Levetin* Faculty of Biological Science, The University of Tulsa, Tulsa, OK 74104, USA

Received 2 November 1994; accepted 28 June 1996

Abstract

Few aerobiological studies have focused on smut spores, of fungi within the order , but the scientific literature provides evidence of the potential aerobiological significance of these plant pathogens. The atmosphere in Tulsa, Oklahoma was monitored for the presence of smut teliospores using a Burkard Volumetric Trap. Smut spores were identified in the atmospheric samples every day from May to October during 1991 and 1992 at concentrations that were normally below 1000 spores/m 3. The peak concentration observed during this study was almost 6000 spores/m 3. Daily concentrations fluctuate due to a variety of factors such as precipitation, relative humidity, percent sunshine, and the phenology of fungi in relation to their hosts. In northeastern Oklahoma, the most prevalent species of smuts in the atmosphere during the spring include Sphacelotheca occidentalis, tritici, and U. kolleri. In the fall, spores of U. brumivora, U. bullata, and U. maydis are more common.

Keywords: Aerobiology; Smut spores; Teliospores; Ustilaginales

1. Introduction The season for production varies for the different smuts. Hamilton (1959) reported that airborne Members of the order Ustilaginales, smuts, create spores of Tilletia peaked in late August and early black, dusty spore masses similar to soot on the plants September while Ustilago spores climaxed between mid- they infect (Alexopoulos and Mims, 1979). There are June and the end of July. As typical of most fungi, the approximately 1200 species of smuts within 50 genera airborne spore concentrations of these two genera de- (Vanky, 1987). The majority of species are classified pend on a number of meteorological factors. Levels into two large genera, Tilletia and Ustilago. Smuts are decrease when conditions are rainy or extremely humid, serious plant pathogens on cereal crops, causing mil- and they increase during periods of brilliant sun, strong lions of dollars in crop damage each year (Alexopoulos winds, and high barometric pressure (Hamilton, 1959). and Mims, 1979). Many native grasses and other plants As members of (tie 'dry air spora', conditions such as are also affected, and the number of hosts for smuts low humidity levels and gusty winds enhance the spore dispersal mechanism employed by the smuts (Hirst, approaches nearly 4000 species. Teliospores are the 1953; Levetin, 1995). characteristic asexual spores of members of Ustilagi- In addition to the aerobiological significance of nales. Typically, teliospores are globose with smooth, teliospores as plant pathogens, it has been suggested echinate, or reticulate sculpting patterns; they have that these spores could serve as potential aeroallergens. yellow to brown pigmented walls and are dispersed by The atmosphere is often saturated with these fungal wind (Alexopoulos and Mims, 1979). spores for an extended period of time. Also, individuals have skin-tested positive for these fungal allergens and *Corresponding author. Tel: + 1 918 6312764; fax: + 1 918 have IgE antibodies to the antigens in their blood 6312762. (Burge, 1985; Santilli et al., 1985). Although some smut

0393-5965/96/$15.00 1996 Elsevier Science Ireland Ltd. All rights reserved PH S0"~93-~965(96)00190-4 178 V. Crotzer, E. Levetin / Aerobiologia 12 (1996) 177-184 extracts are routinely used for diagnosis and desensitiza- 4-5 days until the mounting medium